Problem: What do the following two equations represent? $-x-4y = -4$ $4x+16y = -2$
Explanation: Putting the first equation in $y = mx + b$ form gives: $-x-4y = -4$ $-4y = x-4$ $y = -\dfrac{1}{4}x + 1$ Putting the second equation in $y = mx + b$ form gives: $4x+16y = -2$ $16y = -4x-2$ $y = -\dfrac{1}{4}x - \dfrac{1}{8}$ The slopes are equal, and the y-intercepts are different, so the lines are parallel.